Obturator and Femoral Nerve Block in Patients With Hip Fracture

Analgesic Effect of an Obturator Nerve Block Combined With a Femoral Nerve Block Compared With Femoral Nerve Block Alone in Patients With Hip Fracture

A higher number than expected of patients with hip fracture have only insufficient analgesic effect of a femoral nerve block, which is the nerve block commonly used for this group of patients. One of the possible causes of this failure to provide analgesia from a single nerve block could be the that other nerves are involved in transmitting the pain signal. One of the nerves that is believed to give off branches to the hip is the obturator nerve. With ultrasound it is possible to make a selective proximal nerve block of the obturator nerve. The aim of this trial is to test the analgesic effect of a femoral nerve block i combination with an obturator nerve block compared to femoral nerve block alone in a randomized and placebo controlled design.

A higher number than expected of all patients with hip fracture have only insufficient analgesic effect of a femoral nerve block. One of the possible causes of this failure to provide analgesia from a single nerve block could be the that other nerves are involved in transmitting the pain signal. One of the nerves that is believed to give off branches to the hip is the obturator nerve. Earlier it was believed that the so called '3-in-1-block' or the iliac fascia compartment block would anesthetize also the obturator nerve, and these two nerve blocks have been uses extensively in the emergency ward for preoperative analgesia. Today that is not believed to be true and consequently is the part of the obturator nerve in patients with hip fracture unknown. With ultrasound it is possible to make a selective proximal nerve block of the obturator nerve before it branches into an anterior and a posterior branch. A selective nerve block of the obturator nerve to access its effect in patients with hip fracture has to our knowledge never been done. The aim of this trial is to test the analgesic effect of a femoral nerve block i combination with an obturator nerve block compared to femoral nerve block alone in a randomized and placebo controlled design.

Success rate of successful analgesia, measured with numeric rating scale(NRS) 0-10 with 0=no pain and 10=worst pain. Successful analgesia = NRS<4 at rest and NRS <6 with passive movement of the fractured leg.

Frequency of patients with possible ultrasound visualization of the obturator nerve block injection site

Total morphine equivalent dose of opioid/time from the time of nerve block until the time of operation

Inclusion Criteria: Clinical suspicion of hip fracture Age ≥ 55 years Mentally capable of comprehending and using verbal pain score Mentally capable of differentiating between pain from the fractured hip and pain from other locations Mentally capable of understanding the given information Arrival in the emergency room at times when one of the doctors who do the nerve blocks for this investigation are on call Verbal numeric pain scale score (NRS 0-10) > 5 with a dynamic test OR NRS > 3 at rest Patients informed consent Exclusion Criteria: Hip fracture not confirmed by x-ray Weight < 40 kg Patient has previously been included in this trial If the patient wishes to be excluded Allergy to local anesthetics or adrenocortical hormone Visible infection in the area of the point of needle injection